5 String Project..questions

I am going to buy a Essex 5 string of some type. Probably a Jazz. This bass will be more an exercise in trying new stuff, and taking up some of my free time to tinker with stuff. I have several questions.

1. I have no use for a b string. I was wondering if anyone has restrung there 5 for a C instead on the high side. That would be useful to me. Would it mess up my neck? Where would I get strings...buy a 6 set and just chuck the b in the dump? Any advice?

2. I plan to make this an active setup eventually. Nothing against passives, but I like the variety of sounds I could try to get with an active setup. What kind of money am I looking at here? Not that money is a real issue..I just like to know what stuff goes for so I dont get gouged. Would need some decent pups, and a preamp. 9v vs 18v? Either way I will route out a spot for a battery box instead of trying to hide it somewhere else. Would it be best to go with something like the soapbar style bass they sell vs. a Jazz simply because of pickup availability...or quality?

Yes, you might need to play with the truss rod a bit. A c-string doesn't have the same tension as a low b. There are 5-string packs with c's, but you might have to resort to purchasing online. Then again, shipping might cost enough to just buy the 6-string packs and not use the b.